In horizontal push and pull exercises, the top of the arm (head of the humerus) should stay secured in the shoulder (glenoid fossa) throughout the entire range of motion. The top of the arm may translate forward (relative to the acromion) as the elbows pass behind the hip, which can be a contributing factor in future shoulder pain. This may be brought upon by an excessively rounded (kyphotic) spine and/or forward tipping of the shoulder blade (scapular dyskinesis). However, if the back and shoulder blade are not compromised, you can self-correct by simply monitoring and avoiding this glide. You will often see this at the bottom of a bench press or top of a bent over row.